--- a/execinfo.c
+++ b/execinfo.c
@@ -26,6 +26,7 @@
  * $Id: execinfo.c,v 1.3 2004/07/19 05:21:09 sobomax Exp $
  */
 
+#define _GNU_SOURCE
 #include <sys/types.h>
 #include <sys/uio.h>
 #include <dlfcn.h>
--- a/stacktraverse.c
+++ b/stacktraverse.c
@@ -1,3 +1,4 @@
+#define _GNU_SOURCE
 #include <stddef.h>
 
 #include "stacktraverse.h"
--- a/test.c
+++ b/test.c
@@ -1,3 +1,4 @@
+#define _GNU_SOURCE
 #include <stdio.h>
 #include <stdlib.h>
 
